drm/bridge: dw-hdmi: remove dead code and fix indentation

The hdmi_datamap enum is no longer in use. Also reindent enable_audio's
call params.

Signed-off-by: Adrián Larumbe <adrian.larumbe@collabora.com>
Acked-by: Neil Armstrong <neil.armstrong@linaro.org>
Signed-off-by: Neil Armstrong <neil.armstrong@linaro.org>
Link: https://patchwork.freedesktop.org/patch/msgid/ca42985814e9be33b7f8e3a33cea9e18505299e3.1687702042.git.adrian.larumbe@collabora.com